As if watery eyes, chronic respiratory disease and cancer weren’t enough, now there’s another reason to tamp down air pollution. A new study by economics professor Steven Rivkin, his former student E. Megan Kahn Shaw ’04 and a team of researchers shows that high levels of air pollution markedly increase school absences.

Rivkin, Shaw and their colleagues from Columbia and Stanford universities estimated the effect of air pollution on elementary and middle school absences using data on school attendance and student demographic characteristics between 1986 and 2001 in 39 of the largest school districts in Texas. They matched this information with data on ozone, particulate matter and CO levels, as recorded by pollution monitors maintained by the Environmental Protection Agency. The researchers found that high amounts of CO in particular—including levels that the EPA considers acceptable—increased absenteeism among children.

CO (not to be confused with CO2, the greenhouse gas carbon dioxide) is emitted from incomplete combustions occurring in fires, internal combustion engines, appliances and tobacco smoke, with cars accounting for as much as 90 percent of CO in urban areas. In addition to contributing to global warming, CO has profound effects on humans: by bonding with hemoglobin in the blood, CO impairs the transport of oxygen in the body, which can lead to cardiovascular and respiratory problems.

“Kids are particularly sensitive to pollution, given their small size, high metabolic rates and developing systems,” says Rivkin, who is Amherst’s Rachel and Michael Deutch Professor of Economics. “Our study provides evidence that high CO levels do, in fact, impose substantial costs on children and their families.” He says the research also underscores the need for close monitoring of pollution levels and for more research on the effects of pollution.